What is important to know about 3D printing supports ?

Introduction

3D printing can help you achieve pretty impressive models. But getting your part printed out as neat as it appears on your design may involve in-between steps. 3D printing supports for instance, is one of the first things you may have to take into account based on the additive manufacturing technology you use and the complexity of your design.

Making adapted 3D printing supports brings about a few doubts, such as when they are needed, how to choose from the different types of supports, how to remove them, and of course, what the downsides of using supports are. In this article, we are going to tackle these questions and provide you with a few tips to help you use supports efficiently.

Printing Supports: When to use them?

To settle that question, you first need to know what 3D printing technology you are going to use. If you haven’t made up your mind yet, note that the way 3D printers function raises different technical constraints.

FDM printers, for instance, function by extruding filament layers successively. In other words, if your part includes an overhang that isn’t maintained by any surface underneath, your 3D print is going to fail. This type of issue is one of the main reasons why supports are very useful for FDM prints.

3D printed parts made using Stereolithography also require support structures. These supports are needed to print correctly any overhangs and bridges during the SLA printing process, for example. You can choose the part’s orientation, choosing which exposure requires less support structure.

If you are using Selective Laser Sintering or Jet Fusion technologies, on the other hand, the powder your part is going to be printed out of will surround the print and act as a support. In other words, you will never have to bother with supports if you go for SLS or Jet Fusion technologies. If you are looking into more advanced technologies, the supports that may be used in processes such as metal printing will generally not affect the print quality.

The complexity of your part is the second criterion that will determine whether or not it will need supports. First, if your design contains overhangs, you have to figure out their tilt. If your overhangs don’t tilt more than 45°, most FDM printers will be able to print them properly. If angles exceed this value on the other hand, you might need to use supports or your overhangs are likely to sag.

You might also want to consider using 3D printing supports if a part of your design bridges a gap between two elements. Basically if the length of your bridge doesn’t exceed 5mm, you won’t need any support structure to fill the gap.

What are the different types of 3D Printing supports?

The 3D printing process you have chosen will orient you towards different support types. For FDM printers for instance, the most commonly used supports are the lattice and the tree types.

The first type can be used to build columns and hold parts steady, which is effective with steep overhangs. These lattice structures are the most widespread thanks to how fast they can be generated and to their compatibility with most 3D prints.

Tree type supports start with trunks and evolve in thin branches as they reach the model, which appear to be useful if one needs to selectively support parts. You might consider using such types of support if your design contains many overhangs but aren’t too vertical.

If you can rely on a two-extrusion head printer, you can opt for a soluble support. Soluble materials such as limonene can be loaded in one extruder and be applied along with your printing material. If you are fine with investing in more expensive supports, dissolvable ones will enable you to wash them away by soaking them in water. Using dissolvable supports is the best way to keep a nice surface finish without adding extra steps to your post-processing. Yet, because the soluble support material and 3D printing materials can’t be extruded together, 3D printers with only one print head can’t make such a process. Also, as this last support type suggests, the ease of removing supports is an important criterion to look at when it comes to choosing one.

Removing your 3D Printing supports

We have just seen that lattice, tree-type and dissolvable supports have different properties. On top of that, their ease of removal isn’t equal. Keep in mind that the more your model is in contact with supports, the more likely their removal may result in partial marks or breaks. Lattice structures are for instance supposed to support surfaces completely, which makes them hard to remove without impacting the surface quality.

Tree type supports, if used wisely to support key areas of your parts only, will translate to fewer contacts with your print and make it easier to remove them.

Once the printing process is over, removing the supports is your next step. Using pliers is a good choice if you want to grab, twist and pull your supports off your part. If the support you want to take off is accessible and big enough, you can gently start with your fingers. Depending on how much the visual aspect of your part is important to you and how many marks have been left by your supports, you might need to sand the areas in contact with the supports to get a better surface finish.

The downsides of using 3D printing supports

Using supports implies quite a few limitations and removing them, is as we have seen, definitely part of the list. Another overt drawback of using supports is the increase in lead time.

Depending on the type of support you want to use, its size and complexity, printing supports themselves will add to your total production time. Tree-shape supports can in that sense be quite demanding for your printer. Also, the post-processing steps we have mentioned beforehand need to be taken into account here, since removing the supports off your parts and cleaning them can turn tedious.

The main downside that naturally comes next is the costs of using supports, as the amount of material needed can increase. If steep overhangs account for a big part of your design and you need to use lattice structures to support them, the half of your material can possibly fall into the creation of your supports.

Fortunately, there are multiple ways one can rely on to mitigate the impacts your supports might have on your design and on your wallet.

How to avoid using supports?

If you would like to optimize the integration of your supports, there are multiple options that 3D slicers and your 3D printer can offer you.

When printing supports for your 3D prints, your goal should be to balance the density & thickness of your supports with the cooling speed. To put it simply, the more your supports will be exposed to high temperatures (and the longer it takes to cool off), the more they will stick to your part. Hence the colder they remain, the easier it will be to remove your 3D printing supports.

Apart from having efficient coolers, the density of your supports is going to impact its temperature. Reducing the amount of matter within your supports will help them release heat. If your overhang is long, heavy or especially steep, you might need to make your supports dense to prevent your part from sagging. But keep in mind that the denser and thicker your supports are, the higher goes the risk of damage when removing the supports.

These are parts of the support generation options 3D slicers can help you tweak. But before you get to change that, there are a couple of ways you can optimize your 3D printing support structures in your design.

First of all, you have to figure out which orientation is the most consistent in terms of support generation. If you take a look at the two bridges, you will notice one difference: The second one is flipped upside-down, of course, but unlike the other one, it doesn’t need any support.

If you have already tried to play with the orientation of your part but believe it still requires too many supports, you may be able to tweak your overhangs. If for instance their angles are a bit too round and tilt over 45°, see if you can replace them using a single, less steep angle in your design. Another option you might want to try is to separate your design into two separate models. Going for this solution will definitely help you save on support materials, but in return, you will have to figure out how to reassemble your parts.

We have covered all the key points you need to know about when it comes to 3D printing using supports, or not. Also remember that another way you can get rid of support issues is to switch to a printing technology that doesn’t need any. Selective Laser Sintering 3D printers could in that way help you achieve high geometry 3D prints without dealing with the downsides of 3D printing supports. You can try Sculpteo’s online 3D printing service if you want to have access to SLS printers, and you can also contact us if you have any questions pertaining to your 3D printing needs.

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